Definition
WA is the National Weather Service product code that identifies an AIRMET bulletin. AIRMETs are inflight weather advisories issued for weather phenomena that are of operational interest to all aircraft and that may be hazardous to aircraft with limited capability — particularly those without weather avoidance equipment, anti-icing equipment, or oxygen. WA bulletins cover moderate icing, moderate turbulence, sustained surface winds of 30 knots or greater, widespread ceilings below 1,000 feet and/or visibility below 3 statute miles, and extensive mountain obscuration.
Plain English
WA is the label on a weather report that warns pilots about flying conditions that aren't dangerous to large airliners but can be a real problem for smaller aircraft — things like icing, bumpy air, low clouds, or poor visibility.
Context Anchor
Seen in FAA weather-advisory material and aviation weather products where AIRMETs are identified by the code WA.
Derivation
The 'W' stands for weather and the 'A' for advisory or AIRMET. The code distinguishes AIRMETs (WA) from SIGMETs (WS) and Convective SIGMETs (WST) in the same bulletin family.
Why Pilots Care
It signals an advisory that may require route changes or altitude adjustments for light aircraft.
Intuition Check
WA does not mean Washington in this weather-advisory context. Here, WA is the code for an AIRMET.
Example Sentence 1
During the preflight briefing, the pilot noted an active WA for moderate icing between 8,000 and 14,000 feet along the route.
Example Sentence 2
Pilots check WA products before departure to identify areas of moderate turbulence.